Pathology is the study and diagnosis of diseases by examining body tissues, typically under magnification. Currently, pathologists manually review stained tissue samples on glass slides under an optical microscope to render a diagnosis. Tissue samples are typically prepared with stains by a specialist called a histotechnician. Today, pathologists use an optical microscope to look at slides of tissue samples. This process has not changed much in over 100 years. Due to this manual process, the initial diagnosis and subsequent second opinions may be delayed as the correct slides must be physically delivered to the proper pathologist.
Digitizing the tissue sample images enables easier and faster evaluation without the organization, shipment and management of glass slides. Using digital pathology techniques will speed turnaround time and improve pathologists' overall diagnostic processes. In light of mounting healthcare cost pressures and the pervasive need to digitize a patient's medical record place such techniques and solutions in high demand.
This area of digital pathology is known as Whole Slide Imaging (WSI) in which entire slides are digitally scanned so that they can be viewed on a computer.
In some scenarios, a pathologist reviewing tissue on a glass slide wishes to analyze the boundary area of the tissue sample or the border area between two types of tissue. When using an optical microscope, the pathologist is accustomed to quickly navigating and reviewing the tissue borders at high magnification by fast manual adjustment of the physical glass slide. FIG. 1 illustrates a typical ‘zigzag’ review path 12 of a pathologist near the boundary of the tissue sample 10 mounted on a glass slide 14. FIG. 2 illustrates a typical rendering at high resolution of the border 22 of the tissue sample 20. Note that the area 24 to the left of the border is air whereby the pathologist views only the glass slide. Note also that the edge of the tissue 22 is vertically aligned near the center of the image.
Pathologists, however, are finding it difficult to ‘mimic’ their ultra-fast optical workflow using the new digital workflow because manipulation of the rendered digital image displayed on the monitor is more cumbersome than the physical handling of the glass slide under an optical microscope. For example, prior art image viewers require users to switch between ‘pan’ and ‘rotate’ modes by either (1) clicking on different buttons or (2) by using right mouse click options. Only after the appropriate mode has been selected, can the user manipulate the rendered image in one of these modes. Thus, tracking the boundary of an object while rotating the view such that this boundary is vertical at all times is a daunting task for a pathologist that needs to review dozens of slides per day.
One prior art solution to this problem is to provide the pathologist with an ‘input device’ that simulates the controls of an optical microscope and mimics the physical experience of manual interaction with a glass slide. Such an input device may have knobs and controls that are similar to the ones found on an optical microscope. Such a solution, however, does not take advantage of the digital representation of the image.